Seat adjusting apparatus for vehicle

ABSTRACT

A seat adjusting apparatus includes: a first clutch mechanism; a second clutch mechanism; and a return member having a contact portion and a second engagement portion. The contact portion is configured to come in contact with a roller and is positioned in a wedge-shaped space. The contact portion is located at the side of an area, where a distance between a cam surface of an input side member of a first clutch mechanism and an inner peripheral surface of a control member is reduced. The second engagement portion is engaged in a circumferential direction with a first engagement portion provided at the input side member so that the return member rotates integrally with the input side member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119to Japanese Patent Applications No. 2005-363956, filed on Dec. 16, 2005,No. 2005-377509, filed on Dec. 28, 2005, the entire content of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a seat adjusting apparatus for avehicle, which adjusts a height of a seat cushion. More specifically,the present invention pertains to a clutch mechanism of a seat adjustingapparatus for a vehicle.

BACKGROUND

Conventionally known are seat adjusting apparatuses for vehicles, whichadjust the height of a seat cushion. In such seat adjusting apparatus,the height of the seat cushion is adjustable upon an operation of anoperating lever in cases where an occupant is seated on the seat.

For example, according to a seat adjusting apparatus for a vehicledisclosed in JP2003-93187A (FIGS. 11, 12 and 13), provided are a firstclutch mechanism and a second clutch mechanism. The first clutchmechanism transmits an operation force applied to the operating lever toa control member via an input side member connected to the operatinglever. When the operating lever is not operated, force transmissionbetween the input side member and the control member is cut off.Further, when the operating lever is operated, the second clutchmechanism transmits the operation force to the output shaft via thecontrol member. When the operating lever is not operated, the secondclutch mechanism locks the output shaft against rotation.

In the first clutch mechanism, rollers are arranged in a wedge-shapedspace defined between a cam surface provided at the input side memberconnected to the operating lever and an cylindrical surface of thecontrol member. The control member rotates with the rollers engaged inresponse to rotation of the input side member. When the operating leveris released from being operated, the input side member is returns to theoriginal neutral position.

However, according to the above-described structure, if the rollersrotate slowly relative to the rotation of the input side member in asituation where the input side member returns, the rollers arranged inthe wedge-shaped space wedge-shaped space are occasionally trapped,i.e., engaged, between the cam surface and the cylindrical surface. Inorder to prevent a rotational error due to such engagement, a play isprovided for the rollers in the wedge-shaped space. However, such playcauses deterioration in an operation feeling due to a delayed movementof the rollers relative to the operation of the operating lever.

The present invention has been made in view of the above circumstancesand provides a seat adjusting apparatus for a vehicle in which anoperational performance of the operating member at the neutral positionis enhanced.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a seat adjustingapparatus for a vehicle having a seat lifted up and down in response toa rotation of an output shaft following an operation of an operatinglever, includes: a first clutch mechanism and a second clutch mechanism.The first clutch mechanism is connected to the operating lever andincludes: an input side member connected to the operating member andhaving a cam surface and a first engagement portion; a control memberhaving an inner peripheral surface facing the cam surface in a radialdirection, a wedge-shaped space being defined between the innerperipheral surface and the cam surface; and at least one roller arrangedin the wedge-shaped space. In the first clutch mechanism, operationforce of the operating member is transmitted to the control member whenthe operating member is operated, and force transmission between theinput side member and the control member is discontinued when theoperating member returns to an original position. The second clutchmechanism includes: a static member housing the output shaft to berotatable. In the second clutch mechanism, operation force of theoperating member is transmitted to the output shaft from the controlmember when the operating member is operated, and the control member isengaged with the static member when the operating member is not operatedso that the output shaft is locked not to rotate. The seat adjustingapparatus further includes a return member having a contact portion anda second engagement portion. The contact portion is configured to comein contact with the roller and is positioned in the wedge-shaped space.The contact portion is located at a side of an area, where a distancebetween the cam surface and the inner peripheral surface is more reducedthan that of an area where the roller is located. The second engagementportion is engaged in a circumferential direction with the firstengagement so that the return member rotates integrally with the inputside member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a seat for a vehicle having a seatadjusting apparatus according to an embodiment of the present invention;

FIG. 2 is a perspective view illustrating the seat adjusting apparatus;

FIG. 3 is an exploded perspective view of a clutch apparatus of the seatadjusting apparatus;

FIG. 4 is a sectional view of the clutch apparatus;

FIG. 5 is a sectional view taken along line V-V in FIG. 4;

FIG. 6 is an explanatory view for explaining an input side member;

FIG. 7 is a sectional view taken along line VII-VII in FIG. 4;

FIGS. 8A and 8B are explanatory views of a return spring;

FIG. 9 is a front view of a spiral spring;

FIGS. 10A, 10B and 10C are explanatory views explaining an operation ofthe input side member; and

FIG. 11 is a perspective view for explaining the clutch apparatus.

DETAILED DESCRIPTION

An embodiment of the present invention is described below with referenceto the attached drawings.

As illustrated in FIGS. 1 and 2, a seat 1 for a vehicle includes a seatcushion 1 a and a seatback 1 b extending in an inclined upward directionfrom a rear end upper surface of the seat cushion 1 a. The seat 1 issupported to be rotatable over lower rails 2 a and 2 b secured to afloor of the vehicle. Provided is a seat adjusting apparatus 3 under theseat cushion 1 a, which adjusts the height or the surface level of theseat cushion 1 a.

The lower rails 2 a and 2 b are mounted with the upper rails 4 a and 4 bslidable over the lower rails 2 a and 2 b. The upper rails 4 a and 4 bsupport base frames 5 a and 5 b of the seat cushion 1 a to be lifted upand down, respectively.

Lifter links 6 a and 7 a are supported at front and rear ends of theupper rail 4 a so as to pivot about lower ends, respectively. The lifterlinks 6 a and 7 a are further connected to front and rear ends of thebase frame 5 a so as to pivot about upper ends, respectively. Likewise,lifter links 6 b and 7 b are supported at front and rear ends of theupper rail 4 b so as to pivot about lower ends, respectively. The lifterlinks 6 b and 7 b are further connected to front and rear ends of thebase frame 5 b so as to pivot about upper ends, respectively. Thejoining point between the lifter link 7 a and the base frame 5 a isconnected to the joining point between the lifter link 7 b and the baseframe 5 b via an approximately cylindrical torque rod 8. Therefore, thebase frames 5 a and 5 b are interlocked with each other to be lifted upand down.

The base frame 5 b is equipped with a clutch mechanism 11 configuringthe seat adjusting apparatus 3. An operating lever 12, which serves asan operating member, is attached to the clutch mechanism 11. A piniongear 13 is mounted at an output shaft of the clutch mechanism 11. Thepinion gear 13 rotates in response to operation of the operating lever12. A sector gear 14 is supported at the base frame 5 b behind theclutch mechanism 11 so as to rotate about its lower base end. The sectorgear 14 is formed, at a distal end, with teeth 14 a engaged with thepinion gear 13. The sector gear 14 is hence rotated in response torotation of the pinion gear 13. An upper base end of the sector gear 14is connected to an upper end of the lifter link 7 b via the driving link15 in a manner that the driving link 15 allows the sector gear 14 andthe lifter link 7 b to pivotably rotate. Therefore, once the sector gear14 is pivoted, the lifter link 7 b is pivoted via the driving link 15and the litter link 7 a is pivoted via the torque rod 8, wherein thebase frames 5 a and 5 b are interlocked with each other to be lifted upor down.

Described below is a detailed structure of the clutch mechanism 11. Asillustrated in FIGS. 3 and 4, the clutch mechanism 11 includes anapproximately cylindrically shaped case 21 as a static member. Asillustrated in FIG. 5, the case 21 is fixedly attached to the base frame5 b via multiple attaching portions 21 a protruding outwardly in aradial manner. Further, as illustrated in FIG. 6, the case 21 is formedwith a hook portion 21 b and engagement strips 21 c (see FIGS. 10A, 10Band 10C) protruding in the axial direction. The case 21 is formed with areduced diameter portion 21 e as a cylindrical portion at the side ofthe operating lever 12 and an enlarged diameter portion 21 f as acylindrical portion at the opposite side to the operating lever 12. Thereduced diameter portion 21 e is connected to the enlarged diameterportion 21 f via a stepped portion 21 j extending in a radial direction.An output shaft 22 is positioned inside the case 21 and is freelyrotatably supported by the base frame 5 b.

The output shaft 22 is integrally formed with a rotor cam 23 at the sideof the operating lever 12 of the base frame 5 b. The output shaft 22 isfurther formed integrally with the pinion gear 13 at an opposite side tothe operating lever 12 of the base frame 5 b. The rotor cam 23 exhibitsan approximately hexagonal shape having an outer surface as a camsurface 23 a and grooves 23 b each defined at an intermediate of thecorresponding edge of the hexagonal surface. According to the embodimentof the present invention, the rotor cam 23 and the pinion gear 13 areeach formed integrally with the output shaft 22. However, the rotor cam23 and the pinion gear 13 can be each separated from the output shaft 22and can rotate integrally therewith.

Further, the output shaft 22 supports an input side member 24 to befreely rotatable, which input side member 24 is attached with theoperating lever 12. As illustrated in FIG. 4, the input side member 24includes an inner race 25, which is formed in an approximatelycylindrical shape and into which the output shaft 22 is inserted, and aplanar-shaped lever contact portion 26, which extends from the innerrace 25 outwardly in a radial manner. As illustrated in FIG. 6, thelever contact portion 26 are formed with plural bores 26 a (three boresin FIG. 6) into which the operating lever 12 is fitted. The bores 26 aare arranged in the circumferential direction. Therefore, the input sidemember 24 can rotate in response to operation of the operating lever 12.As is apparent from FIG. 11, the lever contact portion 26 is furtherformed with a hook portion 26 b extending axially and protrusions 26 cwhich come in contact with the engagement strips 21 c in acircumferential direction. The lever contact portion 26 is still furtherformed with (or still further includes) through bores 26 d (firstengagement portions, see FIG. 3) penetrating in the axial direction. Asillustrated in FIGS. 10A, 10B and 10C, the protrusions 26 c of the inputside member 24 come in contact with the engagement strips 21 c of thecase 21 in response to rotation of the input side member 24, wherein arotation range of the input side member 24 is restrained. FIG. 10Aillustrates a state in which the protrusions 26 c are in contact withthe engagement strips 21 c in response to a clockwise rotation of theinput side member 24. FIG. 10B illustrates the input side member 24 in aneutral position. FIG. 10C illustrates a state in which the protrusions26 c are in contact with the engagement strips 21 c in response to acounterclockwise rotation of the input side member 24.

As is apparent from FIGS. 3 and 4, attached to a distal end of theoutput shaft 22 are an elastic member 27, which is made of a wavedspring or a disc spring, washers 28 a and 28 b, by means of a bolt 29.The input side member 24 is biased in the axial direction by biasingforce of the elastic member 27. As viewed from a cross section in whichits axis penetrates at right angles in FIG. 7, the inner race 25exhibits an annular shaped inner periphery and approximately pentagonalshaped outer periphery, and the outer peripheral surface of the innerrace 25 serves as a cam surface 25 a.

Further, as illustrated in FIGS. 3 and 4, a return member 31 and acontrol member 32 are arranged at a radially outward side of the inputside member 24 inside the case 21. The return member 31 is idly fittedat a radially outward side of the inner race 25. The return member 31includes a cylindrical portion 31 a and plural contact portions 31 bextending in the axial direction from the cylindrical portion 31 a andprotruding to the opposite side to the operating lever 12. The quantityof the contact portions 31 b of the return member 31 depends of theshape of the inner race 25 of the input side member 24. According to theembodiment of the present invention, there are five contact portions 31b arranged at the same interval in the circumferential direction. Thereturn member 31 is further formed with (or further includes) a hookportion 31 c axially extending and projections 31 d (second engagementportions) axially fixed into the through bores 26 d. According to theembodiment, there is a clearance defined in the circumferentialdirection at the mating portion of each through bore 26 d and thecorresponding projection 31 d.

The control member 32 is idly fitted at the radially outward side of thereturn member 31. The control member 32 includes an annular shaped outerrace 32 a, first engagement portions 32 b and second engagement portions32 c. The first and second engagement portions 32 b and 32 c protrudealong the axial direction from the outer race 32 a to the opposite sideto the operating lever 12 and are arranged in turn along thecircumferential direction. The outer race 32 a is positioned at theradially outward side of the contact portions 31 b of the return member31. A diameter of the outer peripheral surface of the outer race 32 a isapproximately identical to the diameter of the inner circumferentialsurface of the reduced diameter potion 21 e of the case 21. Each firstengagement portion 32 b is fitted with a predetermined looseness intothe corresponding groove 23 b of the rotor cam 23. Each secondengagement portion 32 c is formed into an approximately L-shapedstructure having a stepped portion 32 e extending radially outwardlyfrom the outer race 32 a. A portion of each second engagement portion 32c, which extends axially, is arranged to be radially more outward thanthe first engagement portions 32 b.

As illustrated in FIGS. 4 and 7, multiple spaces (five) are defined,which are surrounded by the cam surface 25 a of the inner race 25, theinner circumferential surface 32 d of the outer race 32 a of the controlmember 32, the return member 31 and the rotor cam 23. The five spacesare arranged along the cam surface 25 a and are separated by the contactportions 31 b. Because the inner circumferential surface 32 d of thecontrol member 32 exhibits an approximately cylindrical shape and thecam surface 25 a of the inner race 25 exhibits a polygonal shape, eachspace exhibits a shape where a distance between the innercircumferential surface 32 d of the control member 32 and the camsurface 25 a of the inner race 25 is gradually reduced towards its endsin the circumferential direction. As illustrated in FIG. 7, each spacehouses therein two first rollers 33, and a first looseness preventivespring 34 is inserted into the two first rollers 33. The first rollers33 transit operation force of the operating lever 12 from the camsurface 25 a of the inner race 25 of the input member 24 to the innercircumferential surface 32 d of the outer race 32 a of the controlmember 32. As illustrated in FIG. 3, the first looseness preventivespring 34 includes spring portions 34 a each arranged between thecorresponding first rollers 33 and a connecting portion 34 b connectingthe plural spring portions 34 a. Each spring portion 34 a biases thefirst rollers 33 arranged at both circumferential sides thereof andexerts a biasing force in the same directions. Accordingly, each springportion 34 a biases the first rollers 33 toward the tops of the innerrace 25 having the outer peripheral surface formed into an approximatelypolygonal shape, i.e., biases the first rollers 33 toward ends of thecorresponding space which is a narrowed and wedge-shaped space definedby the cam surface 25 a of the inner race 25 and the circumferentialsurface 32 d of the control member 32 facing the cam surface 25 a in theradial direction. According to the embodiment, the cam surface 25 a ofthe input member 24, the inner circumferential surface 32 d of thecontrol member 32 and each spring portion 34 a are structured in amanner that the first rollers 33 are not displaced due to a play orlooseness in the wedge-shaped space in the case of a neutral position.

As illustrated in FIGS. 3 and 7, the first clutch mechanism 41 isstructured, as described above, with the input member 24 (inner race24), the return member 31, the first rollers 33, the first loosenesspreventive spring 34 and the control member 32.

As is apparent from FIGS. 4 and 5, defined are plural spaces, which aresurrounded by the cam surface 23 a of the rotor cam 23, the innercircumferential surface 21 d of the case 21 and the base fame 5 b andare defined by the second engagement portions 32 c of the control member32. The second engagement portions 32 c are arranged along the camsurface 23 a of the rotor cam 23. According to the embodiment of thepresent invention, there are six spaces being defined. As describedabove, the cam surface 23 a of the rotor cam 23 is formed into apolygonal shape and the inner circumferential surface 21 d of the case21 is formed into a cylindrical shape, which provides a basis of thateach space exhibits a shape in which a distance between the innercircumferential surface 21 d and the cam surface 23 a is reducedgradually towards its circumferential directional ends.

As is obvious from FIG. 5, accommodated in each space are two secondrollers 35 and a second looseness preventive spring 36 inserted into thetwo second rollers 35 in the respective spaces. Going back to FIG. 3,the second looseness preventive spring 36 includes spring portions 36 aeach arranged in the two corresponding second rollers 35 in each spaceand a connecting portion 36 b connecting the plural spring portions 36a. The base portion of each spring portion 36 a is housed in thecorresponding fitting groove 23 b of the rotor cam 23. Each springportion 36 a biases the corresponding second rollers 35 toward the topsof the rotor cam 23 having the outer circumferential surface formed intoan approximately polygonal shape, i.e., biases the corresponding secondrollers 35 toward ends of the corresponding space which is a narrowedand wedge-shaped space defined by the cam surface 23 a of the rotor cam23 and the inner circumferential surface 21 d of the case 21 facing thecam surface 23 a in the radial direction

As illustrated in FIGS. 3 and 6, a second clutch mechanism 42 isstructured, as described above, with the control member 32 (the firstengagement portions 32 b and the second engagement portions 32 c), therotor cam 23, the second rollers 35, the second looseness preventivespring 36 and the case 21. According to the embodiment, the first clutchmechanism 41 and the second clutch mechanism 42 are arranged in thevicinity of each other in the axial direction.

As illustrated in FIGS. 3, 4 and 10, the clutch apparatus 11 furtherincludes a first torsion spring 37 as a first elastic member and asecond torsion spring 38 as a second elastic member. The case 21includes the hook portions 21 b, each of which extends in the axialdirection from the reduced diameter portion 21 e and serves as anelastic member engagement portion, and an engagement portion 21 g asinput side member engagement portion. The hook portion 21 b, which isillustrated at the upper side in FIG. 11, is formed with a firstengagement portion 21 h (first elastic member engagement portion) nearthe reduced diameter portion 21 e. The hook portion 21 b is furtherformed with a second engagement portion 21 i as a second elastic memberengagement portion. The second engagement portion 21 i forms a distalend of the hook portion 21 b and is narrower in the circumferentialdirection than the first engagement portion 21 h. The first engagementportion 21 h is engaged with the first torsion spring 37 while thesecond engagement portion 21 i is engaged with the second torsion spring38.

The input side member 24 is formed with a hook portion 26 b, which isengageable with the first torsion spring 37 and serves as a firstengagement portion, and protrusions 26 c which come in contact with theengagement portions 21 g of the case 21 in the circumferentialdirection. As illustrated in FIG. 8A, the first torsion spring 37 isengaged with the hook portion 21 b of the case 21 and the hook portion26 b of the input side member 24. Therefore, the first torsion spring 37biases the input side member 24 to the neutral position on the basis ofthe hook portion 21 b (first engagement portion 21 h). The rotationrange of the input side member 24 is restrained by a contact of theprotrusions 26 c of the input side member 24 with the engagementportions 21 g in the circumferential direction

The return member 31 is formed with a hook portion 31 c which is engagedwith the second torsion spring 38 and serves as a second engagementportion. As illustrated in FIG. 8B, the second torsion spring 38 isengaged with the hook portion 21 b of the case 21 and the hook portion31 c of the return member 31. Therefore, the second torsion spring 38biases the return member 31 to the neutral position on the basis of thehook portion 21 b (second engagement portion 21 i). The return member 31is formed with the projections 31 d engaged with the lever contactportion 26 of the input side member 24 in a manner that the returnmember 31 rotates integrally with the input side member 24 (see FIG. 6)

As illustrated in FIG. 3, the case 21, the input side member 24 and thereturn member 31 are formed with the hook portions 21 b, 26 b and 31 coverlapping in the radial direction. As illustrated in FIG. 8A, the hookportion 21 b of the case 21 and the hook portion 26 b of the input sidemember 24 are engaged with the first torsion spring 37. When the inputside member 24 is rotated, energy is stored at the first torsion spring37. Once the operating lever 12 is released from being operated, theinput side member 24 is returned to the original neutral position by aspring force accumulated at the first torsion spring 37. That is to say,the first torsion spring 37 is configured to store the operation forcewhen the operating lever 12 is operated and to return the input sidemember 24 to the neutral position by the operation force as an elasticforce when the operating lever 12 is not operated.

Further, as illustrated in FIG. 8B, the hook portion 21 b of the case 21and the hook portion 31 c of the return member 31 are engaged with thesecond torsion spring 38. When the input side member 24 rotates, energyis stored at the second torsion spring 38. Once the operating lever 12is released from being operated, a spring force stored in the secondtorsion spring 38 returns the return member 31 to the original neutralposition.

According to the embodiment of the present invention, as illustrated inFIGS. 8A and 8B, a leaf spring 43, as a biasing member, is disposedbetween the hook portion 36 b of the input side member 24 and the hookportion 31 c of the return member 31 so as to bias the return member 31towards the input side member 24.

Further, as illustrated in FIG. 4, the base frame 5 b is firmly attachedwith an auxiliary same 16 at a position where the clutch apparatus 11 issupported. The auxiliary frame 16 is secured, at its base end portion,to the base frame 5 b for example by means of a bolt, and an opening endof the auxiliary frame 16 extends so as to be in parallel to the baseframe 5 b with a predetermined distance.

The auxiliary frame 16 is formed with a through hole to be a firstbearing 17, while the base frame 5 b is formed with a through hole to bea second bearing 18 arranged to be coaxial with the first bearing 17.The second bearing 18 possesses a diameter larger than the one of thefirst bearing 17.

The output shaft 22 is supported, at its axially intermediate portion,by the second bearing 18 so as to be rotatable. The output shaft 22 issupported, at its distal end, by the first bearing 17 so as to berotatable. The teeth 14 a of the sector gear 14 are gear-meshed with thepinion gear 13 between the auxiliary frame 16 and the base frame 5 b.

As illustrated in FIG. 4, the output shaft 22 is formed, at a distal endat the side of the pinion gear 13, with two parallel flat surfaces 22 a.A spiral spring 39 is arranged so as to surround the distal end of theoutput shaft 22. As illustrated in FIG. 9, an inner end 39 a of thespiral spring 39 is shaped so as to face approximately in parallel andforms a bore, into which the distal end of the output shaft 22 isinserted and which comes in contact with the flat surfaces 22 a of theoutput shaft 22. The outer end 39 b of the spiral spring 39 is engagedwith a latch shaft 40 supported between the auxiliary frame 16 and thebase frame 5 b. Therefore, biasing force of the spiral spring 39 appliesa predetermined amount of rotational torque to the output shaft 22 withthe fulcrum of the base frame 5 b. The rotational torque then operatesto lift up the base frames 5 a and 5 b.

Described below is an operation of the seat adjusting apparatus for avehicle provided with the clutch apparatus 11 described above. Asillustrated in FIG. 4, once an operator or user rotates the operatinglever 12 in a direction for lifting up the seat cushion 1 a, the inputside member 24 attached with the operating lever 12 rotates integrallywith the operating lever 12. In this case, the return member 31, ofwhich projections 31 d are fitted into the through bores 26 d of theinput side member 24, rotates integrally with the input side member 24.However, because there is a clearance in the circumferential directionat a mating portion of each through bore 26 d and the correspondingprojection 31 d, the return member 31 rotates after the input sidemember 24 slightly rotates. Therefore, the first rollers 33 areprevented from being engaged in the case of an initial rotation of theinput side member 24 and are operated properly to a positioncorresponding to a rotational position of the input side member 24.

The inner race 25 illustrated in FIG. 7 rotates for example in aclockwise direction in response to rotation of the input side member 24,wherein the first rollers 33, which are arranged between the cam surface25 a of the inner race 25 and the control member 32 in each space, arelocked at the wedge-shaped clearance in a manner that the rollers 33 areengaged not to move. As a result, rotation of the inner race 25 istransmitted to the control member 32. As described above, in the firstclutch mechanism 41, in circumstances where the operating lever 12 isdriven to operate, an operation force of the operating lever 12 istransmitted from the input side member 24 to the control member 32.Further, as illustrated in FIGS. 10A, 10B and 10C, the rotational rangeof the input side member 24 is limited with the protrusions 26 c of theinput side member 24 in contact with the engagement strips 21 c of thecase 21 in the circumferential direction.

Once the control member 32 rotates, the first engagement portions 32 bof the control member 32 come in contact with side surfaces of thecorresponding fitting grooves 23 b of the rotor cam 23, wherein therotor cam 23 is rotated in the clockwise direction in FIG. 3. Here, thesecond rollers 35, which are arranged between the cam surface 23 a ofthe rotor cam 23 and the inner peripheral surface 21 d of the case 21,are pushed by the second engagement portions 32 c in the rotationaldirection of the rotor cam 23. Therefore, the second rollers 35 are notlocked or engaged at the wedge-shaped clearance in each space in amanner that the second rollers 35 move. That is, the output shaft 22rotates in response to operation of the operating lever 12. In suchcircumstances, because the clearance defined between each second roller35 and the corresponding second engagement portion 32 c is smaller thanthe clearance defined in the circumferential direction between the baseportion of each spring portion 36 a and the corresponding firstengagement portion 32 b, once the control member 32 rotates, the secondengagement portions 32 c push the second rollers 35 in thecircumferential direction and the first engagement portions 32 b thenpush wall surfaces of the fitting grooves 23 b, wherein the output shaft22 rotates smoothly. As described above, in the second clutch mechanism42, when the operating lever 12 is driven to operate, operation force ofthe operating lever 12 is transmitted to the output shaft 22 from thecontrol member 32. Therefore, the sector gear 14, which is engaged withthe pinion gear 13 of the output shaft 22, is rotated. The lifter links7 a and 7 b pivotably rotate via the driving link 15 on the basis ofrotation of the sector gear 14. As a result, the base frames 5 a, 5 band the seat cushion 1 a are lifted up. Here, biasing force of thespiral spring 39 exerts in a direction for assisting rotation of theoutput shaft 22, wherein operation force of the operating lever can bereduced.

Once the operating lever 12 is released from being operated, the outputshaft 22 rotates counterclockwise in FIG. 5 due to load such as theweight of the seat 1 and/or a weight of an occupant. Here, the outputshaft 22 and the rotor 23 rotate integrally. In response to rotation ofthe rotor cam 23, likewise as the above, the second rollers 35, whichare arranged between the cam surface 23 a of the rotor cam 23 and theinner peripheral surface 32 d of the case 21, are locked at thewedge-shaped clearance in a manner that the rollers 35 are engaged notto move. Because the case 21 is secured to the base frame 5 b, theoutput shaft 22 is prevented from rotating. That is, in the secondclutch mechanism 42, when the operating lever 12 is not driven tooperate, the output shaft 22 is restrained from rotating. Here, becausethe clearance defined between the second rollers 35 and thecorresponding first engagement portion 32 b is smaller than theclearance defined in the circumferential direction between the baseportion of each spring portion 36 a and the corresponding firstengagement portion 32 b, the second rollers 35 are my locked or engagedat the wedge-shaped clearance in a manner that the rollers 35 are notmoved while the first engagement portions 32 b of the control member 32are not pushed by the wall surfaces of the fitting grooves 23 b.

Upon the operating lever 12 is released from being operated as describedabove, the return member 31 and the input side member 24 are biased bythe first torsion spring 37 and the second torsion spring 38 to rotateback to the neutral positions. Here, the first rollers 33 rotate, by thecontact portions 31 b of the return member 31, in the same rotationaldirection as the return member 31 and the input side member 24, whereinthe first rollers 33 are not locked or engaged and are movable.Therefore, the first rollers 33 are not restrained from returning to theneutral position. That is, in the first clutch mechanism 41, when theoperating lever 12 returns to the original position thereof, torquetransmitting between the input side member 24 and the control member 32is cut off.

According to the embodiment of the present invention, the input sidemember 24 and the return member 31 rotate integrally with the throughbores 26 d being fitted with the projections 31 d. Therefore, when theinput side member 24 goes back to the original neutral position, thefirst rollers 33 are forced to rotate by the contact portions 31 b inthe wedge-shaped space between the cam surface 25 a of the input sidemember 24 and the inner circumferential surface 32 d of the controlmember 32. Here, the contact portions 31 b are positioned at the sideswhere a distance between the cam surface 25 a and the innercircumferential surface 32 d is gradually reduced, that is to say, thecontact portions 31 b is located at a side of an area where a distancebetween the cam surface 25 a and the inner peripheral surface 32 d ismore reduced than that of an area where the roller 33 is located.Therefore, even if a play does not exist in the wedge-shaped spacedefined in the first clutch mechanism 41, it is possible to prevent anevent that the input side member 24 can not rotate by the locking or theengagement of the first rollers 33 at the wedge-shaped space when theinput side member 24 goes back to the original neutral position by therelease operation of the operating lever 12.

Especially, according to the embodiment of the present invention, in thecase where the second torsion spring 38, which biases the return member31 toward the original neutral position upon rotation of the returnmember 31, is provided, if the return member 31 is not structured so asto rotate integrally with the input side member 24, the return member 31is biased to the neutral position by the second torsion spring 38,wherein the first rollers 33 are easily engaged in the wedge-shapedspace. According to the embodiment of the present invention, the returnmember 31 is engaged with the input side member 24 and rotatesintegrally in the circumferential direction so that the first rollers 33can be prevented from being engaged.

Further, the leaf spring 43 biases the hook portion 31 c of the returnmember 31 towards the hook portion 26 b of the input side member 24.Therefore, when the return member 31 returns to the neutral position,the return member 31 is applied with biasing force of the leaf spring 43towards the input side member.

When the operating lever 12, which has been operated to lift up the seat1, rotates to the neutral position, the clutch apparatus 11 operates inthe same manner as the case where the operating lever 12 is releasedfrom being operated. Therefore, the rotation of the operating lever 12is not limited. Further, when the operating lever 12 is operated torotate in a direction for lifting down the seat 1, the clutch apparatus11 rotates in an opposite direction and functions in the same manner.Therefore, the operation of the clutch apparatus 11 for the case inwhich the operating lever 12 is operated to rotate in the direction forlifting down the seat 1 will be omitted herein.

The following effects are obtained according to the embodiment of thepresent invention.

(1) The return member 31 rotates integrally with the input side member24. Therefore, when the input side member 24 rotates and returns to theoriginal neutral position in response to releasing of the operatinglever 12 from an operated state, the first rollers 33 rotate with thecontact portions 31 b arranged at the sides, where the distance betweenthe cam surface 25 a and the inner circumferential surface 32 d isnarrowed, in each wedge-shaped space. As described above, the firstrollers 33 are forced to move in response to rotation of the input sidemember 24, wherein it is possible to prevent an event that the inputside member 24 can not rotate by the locking or the engagement of thefirst rollers 33 at the wedge-shaped space when the input side member 24goes back to the original neutral position by the release operation ofthe operating lever 12. Therefore, it is possible to reduce an amount ofplay in each wedge-shaped space and to improve an operation performanceof the operating lever 12 in the neutral position.

(2)

Provided is the leaf spring 34 which biases the return member 31 towardsthe input side member 24. Therefore, when the operating lever 12 isreturned to the original neutral position after the rotation of theinput side member 24 and the return member 31 in response to anoperation of the operating lever 12, the return member 31 is biasedtoward the input side member 24 and rotates integrally with the inputside member 24.

Conventionally, there is a seat for a vehicle provided with a seatadjusting apparatus, which adjusts the height or the surface level of aseat cushion. In such seat adjusting apparatus for a vehicle, the heightof the seat cushion can be adjusted in a case where an occupant isseated on the seat.

The seat adjusting apparatus outputs torque in a normal direction or areverse direction in response to an operation of an operating lever andadjusts the height of the seat cushion. Further, the seat adjustingapparatus includes a first clutch and a second clutch which retains theseat cushion at the appropriate height or position in a state where theoperating lever has been released.

Once an operation force is applied to the operating lever, the operationforce is transmitted to an output shaft via the first and secondclutches. The second clutch prohibits the output shaft from rotatingwhen the operating lever is not driven to operate. The seat adjustingapparatus further includes: a torsion spring returning the input sidemember connected to the operating lever when the operating lever is notinputted with an operation force; and a stopper restraining a rotationalrange of the input side member when the operating lever is operated.

Therefore, an outer race of the second clutch mechanism includes aflange serving as a stopper for restraining a rotation of the input sidemember and an engagement portion engaged with a torsion spring, asdisclosed in JP2003-93187A (FIG. 20).

However, the flange is formed by incising a flat portion of the outerrace, which may deteriorate a mechanical rigidity of the outer race.This may require a process for working the incised portion. Further,because the flange is formed by being the incised portion, which limitsthe height of the flange and an axial height. In such circumstances, thetorsion spring, which has a diameter different from the one of the outerrace, is require to be located at the same axial position coaxially withthe outer race. Therefore, it is necessary to increase the diameter ofthe outer race for the purpose of generating a predetermined amount ofspring torque. This however causes upsizing of the apparatus.

The present invention has been made in view of the above circumstancesand provides a seat adjusting apparatus downsized and formed with asimple structure and downsized.

(1) According to the embodiment of the present invention, the hookportion 21 b extends axially from the reduced diameter portion 21 ehousing the first clutch mechanism 41 and the second clutch mechanism42. Therefore, there is no need to apply a notching process or a bendingprocess and so on so that the case 21 can be simply structured.

(2) The hook portion 21 b, which is engaged with the first torsionspring 37 and the second torsion spring 38, extends axially from thereduced diameter portion 21 e. Therefore, the axial length of the hookportion 21 b is not limited and is formed in a way that the first andsecond torsion springs 37 and 38 are engaged appropriate points of thehook portion 21 b respectively. This prevents upsizing of the apparatusin the radial direction and enables to downsize the apparatus.

(3) The engagement portion 21 g, which comes in contact with theprotrusion 26 c of the input side member 24 and restrains rotation ofthe input side member 24, extends in the axial direction from thereduced diameter portion 21 e. Therefore, there is no need to applyadditional processes to the reduced diameter portion 21 e, such as anotching process, a bending process or the like, and the case 21 issimply structured.

(4) The first engagement portion 21 h, which is engaged with the firsttorsion spring 37, and the second engagement portion 21 i, which isengaged with the second torsion spring 38, are formed continuously inthe axial direction. Therefore, because the first and second torsionsprings 37 and 38 can possess any diameters respectively, a radialdirectional size can be reduced by designing the first and secondtorsion springs 37 and 38 having the same diameter, which downsizes theapparatus.

(5) The first engagement portion 21 h, which is engaged with the firsttorsion spring 37, and the second engagement portion 21 i, which isengaged with the second torsion spring 38, are arranged at the sameposition in the circumferential direction. Therefore, a member (the hookportion 21 b) can be shared by the first torsion spring 37 and thesecond torsion spring 38.

The embodiment of the present invention is not limited to the above andcan be modified as follows.

According to the embodiment of the present invention, the return member31 is engaged with the input side member 24 in the circumferentialdirection and rotate integrally with the projections 31 d of the returnmember 31 fitted into the through bores 26 d of the input side member 24in the axial direction. However, the return member 31 can be engagedwith the input side member 24 in another manner. For example, the inputside member 24 can be provided with a projection as the first engagementportion, while the return member 31 can be provided with a recess as thesecond engagement portion. The input side member 24 and the returnmember 31 can rotate integrally with each other with the recess engagedwith the projection.

According to the embodiment, provided is the leaf spring 43 serving asthe biasing member biasing the return member 31 towards the input sidemember 31. More particularly, the leaf spring 43 biases the hook portion31 c of the return member 31 toward the hook portion 26 b of the inputside member 24. However, in substitution for the leaf spring 43, anelastic member such as a rubber can be disposed in a circumferentialdirectional clearance between each through bore 26 d of the input sidemember 24 and the corresponding projection 31 d of the return member 31.

According to the embodiment, the case 21 of the clutch apparatus 11 isdirectly secured to the base frame 5 b. However, the case 21 can besecured to a base supporting the output shaft 22 so as to unitize theclutch apparatus.

According to the embodiment, the seat cushion 1 a is biased by thespiral spring 39 so as to be lifted up. However, the seat cushion 1 acan be biases by another elastic member such as a torsion bar.

According to the embodiment, the cylindrical portion housing the firstclutch mechanism 41 and the second clutch mechanism 42 includes thereduced diameter portion 21 e and the enlarged diameter portion 21 f.However, the shape of the cylindrical portion is not limited to theabove. For example, a portion housing the first clutch mechanism canpossess a diameter approximately identical to the one of a portionhousing the second clutch mechanism.

As described above, the return member rotates integrally with the inputside member. When the input side member rotates and returns to theneutral position when the operating member is driven to operate, thecontact portion, which is located in the wedge-shaped space at the sideof an area, where a distance between the cam surface and the innerperipheral surface is reduced rotates with the roller. Therefore, therotor is forced to move in response to rotation of the input side memberand the rotor is trapped, wherein a rotational error is avoided.Accordingly, a play in the wedge-shaped space can be reduced, and a usercan obtain an appropriate operating feeling when operating the operatingmember, wherein it is possible to enhance an operability of theoperating member at the neutral position.

It is preferable that the seat adjusting apparatus includes the biasingmember biasing the return member towards the input side member. In thiscase, when the input side member is returned to the original neutralposition after the input side member and the return member rotates inresponse to an operation of the operating member, the return member isbiased toward the input side member so that the return member rotatesintegrally with the input side member.

According to the seat adjusting apparatus for a vehicle, it is possibleto enhance an operability of the operating member at the neutralposition.

The principles, of the preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention, which is intended to be protected, is not to beconstrued as limited to the particular embodiment disclosed. Further,the embodiment described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by others,and equivalents employed, without departing from the spirit of thepresent invention. Accordingly, it is expressly intended that all suchvariations, changes and equivalents that fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

1. A seat adjusting apparatus for a vehicle having a seat lied up anddown in response to a rotation of an output shaft following an operationof an operating member, comprising: a first clutch mechanism connectedto the operating member and including: an input side member connected tothe operating member and having a cam surface and a first engagementportion; a control member having an inner peripheral surface facing thecam surface in a radial direction, a wedge-shaped space being definedbetween the inner peripheral surface and the cam surface; and at leastone roller arranged in the wedge-shaped space, wherein operation forceof the operating member is transmitted to the control member when theoperating member is operated, and force transmission between the inputside member and the control member is discontinued when the operatingmember returns to an original position, a second clutch mechanismincluding: a static member housing the output shaft to be rotatable;wherein operation force of the operating member is transmitted to theoutput shaft from the control member when the operating member isoperated, and the control member is engaged with the static member whenthe operating member is not operated so that the output shaft is lockednot to rotate, a return member having a contact portion and a secondengagement portion, the contact portion configured to come in contactwith the roller and positioned in the wedge-shaped space, the contactportion being located at a side of an area, where a distance between thecam surface and the inner peripheral surface is more reduced than thatof an area where the roller is located, the second engagement portionengaged in a circumferential direction with the first engagement portionso that the return member rotates integrally with the input side member.2. A seat adjusting apparatus for a vehicle according to claim 1,further comprising: a biasing member biasing the return member towardsthe input side member.
 3. A seat adjusting apparatus according to claim1, further comprising: an elastic member configured to store theoperation force when the operating member is operated and to return theinput side member to a neutral position by an elastic force based on theoperation force stored therein when the operating member is notoperated.
 4. A seat adjusting apparatus according to claim 3, whereinthe static member includes a cylindrical portion housing the firstclutch mechanism and the second clutch mechanism and the elastic memberengagement portion extending axially from the cylindrical portion andengaged with the elastic member.
 5. A seat adjusting apparatus for avehicle according to claim 1, wherein the control member is arranged ata radially outward side of the input side member and the static memberis arranged at a radially outward side of the control member.
 6. A seatadjusting apparatus for a vehicle according to claim 1, wherein thecontrol member is arranged at a radially outward side of the input sidemember, the static member is arranged at a radially outward side of thecontrol member, the second clutch mechanism prohibits a rotation of theoutput shaft against the static member when the operating member is notoperated, the seat adjusting apparatus further comprising: an elasticmember configured to store the operation force when the operating memberis operated and to return the input side member to a neutral position byan elastic force based on the operation force stored therein when theoperating member is not operated; and the static member including: acylindrical portion housing the first clutch mechanism and the secondclutch mechanism and an elastic member engagement portion extendingaxially from the cylindrical portion and engaged with the elasticmember.
 7. A seat adjusting apparatus according to claim 6, wherein thestatic member includes an input side member engagement portion extendingaxially from the cylindrical portion, and the input side member includesa projection coming in contact with the input side member engagementportion in the circumferential direction so that a rotational range ofthe input side member is restrained.
 8. A seat adjusting apparatusaccording to claim 6, ether comprising: the roller including a pluralityof rollers transmitting the operational force of the operating memberfrom the cam surface of the input side member to the control member, thereturn member holding the rollers and moving the rollers with the inputside member in a circumferential direction when the input side memberreturns to a neutral position; the elastic member including: a firstelastic member for returning the input side member to the neutralposition; a second elastic member for returning the holding member to aneutral position; and the elastic member engagement portion including: afirst elastic member engagement portion axially extending from thecylindrical portion and engaged with the first elastic member; and asecond elastic member engagement portion formed axially continuously atthe first elastic member engagement portion and engaged with the secondelastic member.
 9. A seat adjusting apparatus according to claim 7,further comprising: the roller including a plurality of rollerstransmitting the operational force of the operating member from the camsurface of the input side member to the control member, the returnmember holding the rollers and moving the rollers with the input sidemember in a circumferential direction when the input side member returnsto a neutral position; the elastic member including: a first elasticmember for returning the input side member to the neutral position; asecond elastic member for returning the holding member to a neutralposition; and the elastic member engagement portion including: a firstelastic member engagement portion axially extending from the cylindricalportion and engaged with the first elastic member; and a second elasticmember engagement portion formed axially continuously at the firstelastic member engagement portion and engaged with the second elasticmember.
 10. A seat adjusting apparatus according to claim 8, wherein thefirst elastic member engagement portion and the second elastic memberengagement portion are arranged at the same position in thecircumferential direction.
 11. A seat adjusting apparatus according toclaim 9, wherein the first elastic member engagement portion and thesecond elastic member engagement portion are arranged at the sameposition in the circumferential direction.